Machine safety advice: Think beyond the safety device, Rockwell Automation says
Functional machine safety is moving beyond compliance to consider andpromote profitability, productivity, and sustainability. A holistic strategy for machinery safety thinks beyond devices that can be applied to or around the machine. Contemporary safeguarding solutions incorporate machine lifecycle, standards, functional design, and risk management, and can be deployed globally, according to Dan Hornbeck, global market development manager, Rockwell Automation Safety Initiative. [While the deadline has been extended for 24 months, Rockwell Automation strongly advises not to wait.]
Hornbeck told Control Engineering that the largest educational opportunity in machine safety remains with understanding global standards and implementing functional safety. Control engineers are learning how to incorporate programmable safety devices and consider the wider system, in light of global standards.
Evolution of safety solutions
Conventional thinking –>Contemporary approach
Black box safety approach –> Integrated safety design
Machine shutdown –>Functional safety design
Limited diagnostics –> Robust diagnostics and security features
Machines conform to local standards –> Global standards approach with local adoption
Minimalist approach –> Safe and productive approach
End-user drive –> end-user / machine builder partnerships
Safety component supplier –> safety automation supplier
Source: Control Engineering with information from Rockwell Automation
Rockwell Automation sees efficiency opportunities in safety
While more end-users are partnering with machine builders, in the end, the original equipment manufacturer (OEM) needs to be responsible for delivering the safest machine possible. Rockwell Automation’s safe design program reaches out to help OEMs with risk assessment services. Many smaller OEMs, Hornbeck says, are still struggling with how to perform risk assessment.
"We’re helping them through the process," he says.
Hornbeck provides the following example of thinking beyond about traditional safety concepts. Instead of a single loading area, a robotic work cell could use a dual pallet loading zone (shown on the Rockwell Automation graphic on the right), so a robot can continue to work without waiting for more parts.
Elik Fooks, vice president and general manager, Rockwell Automation Safety, Sensing & Connectivity Business, says while the dual-loading design on the right adds probably less than 10% of the costs, it lowers insurance rates, decreases downtime, and maximizes process throughput.
Fooks and Hornbeck have been helping OEMs meet the Dec. 29. 2009, deadline for the new European Machinery Directive (2006/42/EC), which includes a functional safety mandate. Among key points is the directive no longer uses categories, requires manufacturer to supply reliable parts, and requires compliance for machines that OEMs ship to Europe. Performance levels of various components are available in a downloadable library from BGIA, a German organization providing testing and certification .
Machinery safety standards
Among applicable standards are:
– EN ISO 13849-1:2006 Machinery safety – safety related parts of control system non electrical and simple electrical: This standard is a development of EN 954-1 and provides safety requirements and guiding principles for design and integration of safety-related parts of control system; such as electrical, mechanical, pneumatic and hydraulics technologies.
-EN IEC 62061:2005 Machine safety – functional safety of electrical, electronic and programmable electronic control systems: This is a machinery sector standard based on IEC 61508 primarily for electrical, electronic and programmable electronic systems.
While risk assessments for safety integrity levels (SIL) are similar to thinking used in the directive, SILs do not have to be used in all situations, Fooks says. Categories (Cat1-4) didn’t necessarily require knowledge of reliability data or redundancy, he says. Performance levels (PL) in the new regulation (A-E) are similar to SIL and include a component calculation, Fooks explains, which Rockwell Automation can provide.
Safety technologies can add productivity
Newer safety technologies can help. Rockwell Automation offers safe speed monitoring with guard locking, where, as the name implies, a process may operate at a safer limited speed, direction, or maximum speed, depending on the situation, rather than always lock-down full stop, Fooks says.
Hornbeck and Fooks presented information from a recent ARC Advisory Group report, "Machine Safeguarding Solutions Worldwide Outlook," which ranks Rockwell Automation first for machine safety solutions and second in process safety, behind Invensys. ARC also names Rockwell Automation the global leader in safety solutions, they said. Machine safeguarding is one of the fastest growing segments of the industrial automation market and ARC expects it to increase at a compound annual growth rate of over 4.6% through the year 2013. In the report, ARC says Rockwell Automation:
– Acquired Cedes and ICS Triplex to expand its portfolio into process safety, machine safeguarding systems, and light curtains.
– Made strong inroads in product development for safe motion-controlled solutions with the Minotaur MSR57P dedicated safe-speed monitoring relay.
– Expanded its safety product portfolio with GuardLogix safety PLC and safe motion from the core of the Rockwell Automation business.
– Is building a complete safety solution business with components, systems, and services. Trained machine safety services staff provide long-term support services to machine builders that need to track the latest OSHA, ANSI, EN, and IEC standards.
– Has a strong financial position and continues to acquire expertise and invest in innovation and aggressive research and development.
Also see the Control Engineering machine safety blog.
– Mark T. Hoske, editor in chief, Control Engineering, www.controleng.com